Respiratory potential of maize ( Zea mays L.) roots exposed to hypoxia

• Published in: Environmental and experimental botany 2009, Vol.65 (1), p.107-110
• Main Authors: Vodnik, D., Strajnar, P., Jemc, S., Maček, I.
• Format: Article
• Language: English
• Subjects: adventitious roots; anaerobic conditions; Biological and medical sciences; cell respiration; corn; diameter; dry matter accumulation; dry matter partitioning; electron transfer; Fundamental and applied biological sciences. Psychology; Hypoxia; Indexing in process; Maize; Nodal roots; oxidation; plant adaptation; plant morphology; plant tissues; Q1; Respiratory potential; Root respiration; roots; Seminal roots; Zea mays
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2008.05.005

When hypoxia is not too severe, root aerobic metabolism can be partly supported by oxygen delivery via aerenchymateous tissues. In terms of supplying energy, this adaptation is of special importance in plants with a high metabolic demand, such as maize ( Zea mays L.). The ability of maize to respond to hypoxia by morphological changes is well documented; however, little is known on the potential for oxidative metabolism in different types of maize roots. In our study, we assessed the root respiratory potential in seminal and adventious nodal roots of maize exposed to mild short-term hypoxia. Plants responded to the treatment with an increased portion of nodal roots per total root length, while there were no changes in the biomass of shoots and roots. Thick nodal roots had much higher respiratory potential (Electron Transport System Activity – ETS) than nodal roots of smaller diameter or seminal roots, irrespective of the aeration rate. The only change in ETS under oxygen deficiency was found for seminal roots where oxygen consumption increased by 25%. Increased root porosity was observed in all roots, the increase was higher in nodal roots. On the basis of ETS data and taking into account changes of root morphology, it can be concluded that large changes of root respiratory potential are not involved in the response of maize to hypoxia. Obviously, maize can cover the respiratory needs with shifts in the growth of different root types which inherently differ in their potential aerobic respiration.